Substrate processing method and substrate processing apparatus

ABSTRACT

Processing of applying ultraviolet rays to a front face of an insulating film material formed on a wafer W is performed, whereby a contact angle of the front face thereof becomes smaller. Accordingly, when an insulating film material is applied on the aforesaid front face, the material smoothly spreads, and projections and depressions never occur on a front face of an upper layer insulating film material. Thereby, it is possible to form the insulating film thick and flatter on a substrate.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention is included in a technical field ofsemiconductor device fabrication and the like, and more specifically,relates to a substrate processing method and a substrate processingapparatus for performing, for example, processing by ultraviolet raysfor a front face of an insulating film material applied on a substrate.

[0003] 2. Description of the Related Art

[0004] In processes of semiconductor device fabrication, a layerinsulating film is formed, for example, by an SOD (Spin on Dielectric)system. In this SOD processing system, a layer insulating film is formedby coating a wafer with a coating film while spinning the wafer andperforming chemical processing, heat processing, or the like for thewafer by means of a sol-gel process, a silk method, a speed film method,a fox method, or the like.

[0005] When a layer insulating film is formed by the sol-gel process,for example, first an insulating film material, for example, a solutionin which colloids of TEOS (tetraethoxysilane) are dispersed in anorganic solvent is supplied onto a semiconductor wafer (hereinafterreferred to as “wafer”). Thereafter, the wafer to which the solution issupplied is subjected to gelling processing, and then solvents areexchanged. Subsequently, the wafer on which solvents are exchangedundergoes heat processing.

[0006] In order to form the layer insulating film, for example, thickand flat on the wafer, application of about two to three coats of aninsulating film material on the wafer is conventionally performed.However, the front face of the insulating film material after theapplication is generally large in contact angle, and thus there is aproblem that when an insulating film material is further applied on thefront face of the insulating film material, a front face of an upperlayer insulating film material becomes uneven.

SUMMARY OF THE INVENTION

[0007] The present invention is made under the aforesaid circumstancesand an abject thereof is to provide a substrate processing method and asubstrate processing apparatus capable of forming an insulating filmthick and flatter on a substrate.

[0008] Another object of the present invention is to provide a substrateprocessing method and a substrate processing apparatus capable ofefficiently making a front face of an insulating film material smallerin contact angle.

[0009] To solve the aforesaid problem, according to a first aspect ofthe present invention, a substrate processing method, comprising thesteps of: applying an insulating film material on a substrate;performing processing by ultraviolet rays for a front face of theapplied insulating film material; and further applying an insulatingfilm material on the applied insulating film material after theultraviolet-ray processing step, is provided.

[0010] According to the above configuration, processing by ultravioletrays, for example, processing including ultraviolet-ray irradiation isperformed for the front face of the insulating film material, wherebythe contact angle of the front face becomes smaller. Therefore, when aninsulating film material is applied on the aforesaid front face by, forexample, spin coating, the material smoothly spreads, and projectionsand depressions never occur on a front face of an upper layer insulatingfilm material. Consequently, it is possible to form the insulating filmthick and flatter on the substrate.

[0011] According to a second aspect of the present invention, asubstrate processing method, comprising the steps of: applying aninsulating film material on a substrate; applying ultraviolet rays to afront face of the insulating film material in an inert gas atmosphere;and thereafter bringing an atmosphere over the insulating film materialto an oxygen atmosphere, is provided.

[0012] According to the above configuration, processing by ultravioletrays, for example, processing including ultraviolet-ray irradiation isperformed for the front face of the insulating film material, wherebythe contact angle of the front face becomes small. Therefore, when amaterial of some kind is applied on the aforesaid front face by, forexample, spin coating, the material smoothly spreads, and projectionsand depressions never occur on a front face of the material.

[0013] According to a third aspect of the present invention, a substrateprocessing apparatus, comprising: a holding plate for holding asubstrate; an ultraviolet-ray irradiation lamp disposed above theholding plate for applying ultraviolet rays to a front face of thesubstrate; means for bringing a portion between the substrate held onthe holding plate and the ultraviolet-ray irradiation lamp to an inertgas atmosphere; and means for switching at least the inert gasatmosphere over the front face of the substrate held on the holdingplate to an oxygen atmosphere, is provided.

[0014] In the above configuration, the portion between the substrateheld on the holding plate and the ultraviolet-ray irradiation lamp isbrought into the inert gas atmosphere, ultraviolet rays are applied ontothe substrate from the ultraviolet-ray irradiation lamp, and thereafterthe inert gas atmosphere over the front face of the substrate isswitched to the oxygen atmosphere, so that a front face of an insulatingfilm can be efficiently made smaller in contact angle.

[0015] According to a fourth aspect of the present invention, asubstrate processing apparatus, comprising: a holding plate for holdinga substrate and ascendable and descendable between a first area and asecond area below the first area; a vertically driving mechanism forvertically driving the holding plate between the first area and thesecond area; an ultraviolet-ray irradiation lamp disposed above theholding plate for applying ultraviolet rays to a front face of thesubstrate held by the holding plate; means for blasting an inert gastoward the first area; and means for blasting oxygen gas toward thesecond area, is provided.

[0016] According to the above configuration, the inert gas atmospherecan be switched to the oxygen atmosphere only by lowering the substratefrom the first area to the second area, and the oxygen atmosphere can beswitched to the inert gas atmosphere only by raising the substrate fromthe second area to the first area. Consequently, a front face of aninsulating film can be efficiently made smaller in contact angle byraising and lowering the substrate above the holding plate.

[0017] According to a fifth aspect of the present invention, a substrateprocessing apparatus, comprising: a holding plate for holding asubstrate to be ascendable and descendable between a first area and asecond area below the first area; a vertically driving mechanism forvertically driving the substrate held by the holding plate between thefirst area and the second area; an ultraviolet-ray irradiation lampdisposed above the holding plate for applying ultraviolet rays to afront face of the substrate held by the holding plate; means forblasting an inert gas toward the first area; and means for blastingoxygen gas toward the second area, is provided.

[0018] According to the above configuration, the inert gas atmospherecan be switched to the oxygen atmosphere only by lowering the holdingplate holding the substrate from the first area to the second area, andthe oxygen atmosphere can be switched to the inert gas atmosphere onlyby raising the holding plate from the second area to the first area.Consequently, a front face of an insulating film can be efficiently madesmaller in contact angle by raising and lowering the holding plate.

[0019] According to a sixth aspect of the present invention, a substrateprocessing apparatus, comprising: a holding plate for holding asubstrate and rotatable; a rotationally driving mechanism forrotationally driving the holding plate; an ultraviolet-ray irradiationlamp, disposed above the holding plate along at least a radial directionof rotation of the holding plate, for applying ultraviolet rays to thesubstrate held by the holding plate; an inert gas blast portion,disposed along one side of the ultraviolet-ray irradiation lamp, forblasting an inert gas toward the front face of the substrate held on theholding plate; and an oxygen gas blast portion, disposed along the otherside of the ultraviolet-ray irradiation lamp, for blasting oxygen gastoward the front face of the substrate held on the holding plate, isprovided.

[0020] According to the above configuration, when the holding plate isrotated, the inert gas is first blasted to the front face of thesubstrate held on the holding plate, whereby the front face of thesubstrate is brought into the inert gas atmosphere and then irradiatedwith ultraviolet rays. Thereafter, the oxygen gas is blasted to thefront face of the substrate, whereby the front face of the substrate isbrought into the oxygen atmosphere. The holding plate is continuouslyrotated, whereby the aforesaid operations are repeated. Consequently, afront face of an insulating film can be efficiently made smaller incontact angle.

[0021] These objects and still other objects and advantages of thepresent invention will become apparent upon reading the followingspecification when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a plan view of an SOD processing system according to anembodiment of the present invention;

[0023]FIG. 2 is a front view of the SOD processing system shown in FIG.1;

[0024]FIG. 3 is a rear view of the SOD processing system shown in FIG.1;

[0025]FIG. 4 is a perspective view of a main wafer transfer mechanism inthe SOD processing system shown in FIG. 1;

[0026]FIG. 5 is a front view showing the structure of an ultraviolet-rayprocessing station according to a first embodiment of the presentinvention;

[0027]FIG. 6 is a processing flowchart of the SOD processing systemshown in FIG. 1;

[0028]FIG. 7 is a front view showing the structure of an ultraviolet-rayprocessing station according to a second embodiment of the presentinvention;

[0029]FIG. 8 is a front view showing the structure of an ultraviolet-rayprocessing station according to a third embodiment of the presentinvention;

[0030]FIG. 9 is a front view showing the structure of an ultraviolet-rayprocessing station according to a fourth embodiment of the presentinvention;

[0031]FIG. 10 is a plan view of the ultraviolet-ray processing stationshown in FIG. 9;

[0032]FIG. 11 is a plan view of a low-oxygen curing and coolingprocessing station;

[0033]FIG. 12 is a sectional view of the low-oxygen curing and coolingprocessing station shown in FIG. 11;

[0034]FIG. 13 is a front view showing the structure of anultraviolet-ray processing station according to a fifth embodiment ofthe present invention; and

[0035]FIG. 14 is a sectional view of a low-oxygen curing and coolingprocessing station according to an eighth embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0036] Hereinafter, a first embodiment of the present invention will bedescribed with reference to the drawings.

[0037] In this first embodiment, a substrate processing method of thepresent invention is applied to an SOD (Spin on Dielectric) processingsystem for forming a layer insulating film on a wafer. FIG. 1 to FIG. 3are views showing the entire structure of the SOD processing system,FIG. 1 is a plan view, FIG. 2 is a front view, and FIG. 3 is a rearview.

[0038] The SOD processing system 1 has a structure in which a cassetteblock 10 for transferring a plurality of, for example, 25 semiconductorwafers (hereinafter, referred to as wafers) W as substrates, as a unit,in a wafer cassette CR from/to the outside into/from the system andcarrying the wafer W into/out of the wafer cassette CR, a processingblock 11 in which various kinds of processing stations each forperforming predetermined processing for the wafers W one by one in anSOD coating process are multi-tiered at predetermined positions, and acabinet 12 in which a bottle of ammonia water, a bubbler, a drainbottle, and the like required in an aging process are provided areintegrally connected.

[0039] In the cassette block 10, as shown in FIG. 1, a plurality of, forexample, up to four wafer cassettes CR are mounted with respective wafertransfer ports facing the processing block 11 side at positions ofprojections 20 a on a cassette mounting table 20 in a line in anX-direction. A wafer transfer body 21 movable in the direction ofarrangement of cassettes (the X-direction) and in the direction ofarrangement of wafers housed in the wafer cassette CR (a Z-verticaldirection) selectively gets access to each of the wafer cassettes CR.The wafer transfer body 21 is structured to be rotatable in aθ-direction so as to be accessible to a transfer and chill plate (TCP)included in a multi-tiered station section of a third group G3 on theprocessing block 11 side as will be described later.

[0040] In the processing block 11, as shown in FIG. 1, a verticaltransfer-type main wafer transfer mechanism 22 is provided at thecentral portion thereof. Around the main wafer transfer mechanism 22,all processing stations composing one group or a plurality of groups aremulti-tiered. In this embodiment, four groups G1, G2, G3, and G4 eachhaving multi-tiered stations are arranged. Multi-tiered stations of thefirst and second groups G1 and G2 are arranged side by side on the frontside of the system (the lower side in FIG. 1), multi-tiered stations ofthe third group G3 are arranged adjacent to the cassette block 10, andmulti-tiered stations of the fourth group G4 are arranged adjacent tothe cabinet 12.

[0041] As shown in FIG. 2, in the first group G1, an SOD coatingprocessing station (SCT) for supplying an insulating film material whilethe wafer W is mounted on a spin chuck in a cup CP and applying auniform insulating film material on the wafer by rotating the wafer anda solvent exchange processing station (DSE) for supplying chemicals forexchange such as HMDS, heptane, and the like while the wafer W ismounted on a spin chuck in a cup CP and exchanging a solvent in theinsulating film applied on the wafer for another solvent prior to adrying process are two-tiered from the bottom in order.

[0042] In the second group G2, an SOD coating processing station (SCT)is arranged at the upper tier. Incidentally, it is possible to arrangean SOD coating processing station (SCT), a solvent exchange processingstation (DSE), or the like at the lower tier of the second group G2 ifnecessary.

[0043] As shown in FIG. 3, in the third group G3, two low-oxygen andhigh-temperature heat processing stations (OHP), a low-temperature heatprocessing station (LHP), two cooling processing stations (CPL), atransfer and chill plate (TCP), and a cooling processing station (CPL)are multi-tiered from the top in order. The low-oxygen andhigh-temperature heat processing station (OHP) here has a hot plate onwhich the wafer W is mounted inside a sealable processing chamber,exhausts air from the center of the top portion of the processingchamber while N₂ is being discharged uniformly from holes at the outerperiphery of the hot plate, and performs high-temperature heatprocessing for the wafer W in a low-oxygen atmosphere. Thelow-temperature heat processing station (LHP) has a hot plate on whichthe wafer W is mounted and performs low-temperature heat processing forthe wafer W. The cooling processing station (CPL) has a chill plate onwhich the wafer W is mounted and performs cooling processing for thewafer W. The transfer and chill plate (TCP) has a two-tiered structurewith a chill plate for cooling the wafer W at the lower tier and adelivery table at the upper tier and performs transfer of the wafer Wbetween the cassette block 10 and the processing block 11.

[0044] In the fourth group G4, a low-temperature heat processing station(LHP), a low-oxygen curing and cooling processing station (DCC), anultraviolet-ray processing station (UV) according to the presentinvention, a low-oxygen curing and cooling processing station (DCC), andan aging processing station (DAC) are multi-tiered from the top inorder. The low-oxygen curing and cooling processing station (DCC) herehas a hot plate and a chill plate such that they are adjacent to eachother inside a sealable processing chamber, and performshigh-temperature heat processing for the wafer W in the low-oxygenatmosphere in which exchange for N₂ is performed and performs coolingprocessing for the wafer W which has been subjected to the heatprocessing. The aging processing station (DAC) introduces a processinggas (NH₃+H₂O) made by mixture of ammonia gas and water vapor into asealable processing chamber to perform aging processing for the wafer W,thereby wet-gelling an insulating film material on the wafer W. Theultraviolet-ray processing station (UV) will be described later. Theultraviolet-ray processing station (UV) is disposed between twolow-oxygen curing and cooling processing stations (DCC), whereby theinside of the station can be kept at a stable temperature.

[0045]FIG. 4 is a perspective view showing the appearance of the mainwafer transfer mechanism 22. This main wafer transfer mechanism 22 isprovided with a wafer transfer device 30 which is ascendable anddescendable in the vertical direction (the Z-direction) inside acylindrical supporter 27 composed of a pair of wall portions 25 and 26which are connected with each other at respective upper ends and lowerends and face each other. The cylindrical supporter 27 is connected to arotating shaft of a motor 31 and rotates integrally with the wafertransfer device 30 around the aforesaid rotating shaft by rotationaldriving force of the motor 31. Accordingly, the wafer transfer device 30is rotatable in the θ-direction. For example, three tweezers areprovided on a transfer base 40 of the wafer transfer device 30. Thesetweezers 41, 42, and 43 each have a shape and a size capable of freelypassing through a side opening 44 between both the wall portions 25 and26 of the cylindrical supporter 27 so as to be movable back and forthalong the X-direction. The main wafer transfer mechanism 22 allows thetweezers 41, 42, and 43 to get access to processing stations disposedthereabout to transfer the wafer W from/to these processing stations.

[0046] It should be noted that this SOD processing system 1 is placed ina clean room by way of example, and an atmosphere over the main wafertransfer mechanism 22 is set at, for example, a pressure higher thanthat of the clean room which is set at atmospheric pressure, therebyejecting particles which occur above the main wafer transfer mechanism22 to the outside of the SOD processing system 1 and additionallypreventing particles in the clean room from entering the SOD processingsystem 1.

[0047]FIG. 11 is a plan view showing the structure of the low-oxygencuring and cooling processing station (DCC) having a heat processingchamber and a cooling processing chamber, and FIG. 12 is a sectionalview thereof.

[0048] The low-oxygen curing and cooling processing station (DCC)includes a heat processing chamber 151 and a cooling processing chamber152 which is provided adjacent to the heat processing chamber 151.

[0049] The heat processing chamber 151 includes a processing chambermain body 153 of which the top portion is opened and a lid body 154disposed to be ascendable and descendable so as to open and close thetop opening portion of the processing chamber main body 153. A raisingand lowering cylinder 155 is connected with the lid body 154, so thatthe lid body 154 is raised and lowered by drive of the raising andlowering cylinder 155. The top opening portion of the processing chambermain body 153 is closed with the lid body 154, whereby a sealed space isformed in the heat processing chamber 151. Further, delivery of thewafer W is performed between the heat processing chamber 151 and themain wafer transfer mechanism 22 and between the heat processing chamber151 and the cooling processing chamber 152 with the top portion of theprocessing chamber main body 153 being opened.

[0050] A hot plate 156 for performing heat processing for the wafer W isdisposed nearly at the central portion of the processing chamber mainbody 153. In the hot plate 156, for example, a heater (not shown) isembedded, and the set temperature thereof can be, for example, 200° C.to 470° C. Further, a plurality of, for example, three holes 157concentrically and vertically penetrate the hot plate 156, and supportpins 158 for supporting the wafer W are inserted in the holes 157 to beascendable and descendable. The support pins 158 are connected to acommunicating member 159 into one body under the rear face of the hotplate 156, and the communicating member 159 is raised and lowered by araising and lowering cylinder 160 disposed thereunder. The support pins158 protrude and retract from the front face of the hot plate 156 byraising and lowering operation of the raising and lowering cylinder 160.

[0051] Moreover, a plurality of proximity pins 161 are disposed on thefront face of the hot plate 156, thereby preventing the wafer W fromdirectly contacting the hot plate 156 when heat processing is performedfor the wafer W. Thereby, electrostatic is prevented from building up inthe wafer W during the heat processing.

[0052] Furthermore, a ring pipe 163 provided with a large number of gasblast ports 162 for supplying an inert gas, for example, nitrogen gas(N₂) into the heat processing chamber 151 is disposed to surround theperiphery of the hot plate 156. This ring pipe 163 is connected to anitrogen gas cylinder 165 via a pipe 164, and an open/close valve 166 isplaced on the pipe 164, and the open/close valve 166 is configured suchthat its opening and closing is controlled by a control section 167. Itshould be noted that not only an inert gas, but also another gas, forexample, oxygen gas may be supplied into the heat processing chamber 151as required. In that case, it is possible to supply these gasses via aswitching valve for switching between nitrogen gas and oxygen gassharing the ring pipe 163. Thereby, upsizing of the heat processingchamber can be avoided.

[0053] Meanwhile, an exhaust port 168 for reducing pressure is providednearly at the central portion of the lid body 154, and the exhaust port168 is connected to a vacuum pump 170 via a flexible hose 169 by way ofexample. By operation of the vacuum pump 170, the inside of the heatprocessing chamber 151 can be set at a pressure lower than atmosphericpressure, for example, about 0.1 torr.

[0054] Further, a current plate 171 is disposed inside the lid body 154to cover the exhaust port 168. The current plate 171 is larger indiameter than the exhaust port 168 and has a clearance of, for example,about 5 mm between the current plate 171 and the inner wall of the lidbody 154. By virtue of the arrangement of such a current plate 171, thepressure in the heat processing chamber 151 can be uniformly reduced.

[0055] Moreover, attached to the lid body 154 is a pressure sensor 172for measuring the pressure in the heat processing chamber 151. Ameasured result by the pressure sensor 172 is reported to the controlsection 167, and the control section 167 controls the operation of thevacuum pump 170 based on the measured result to thereby keep the insideof the heat processing chamber 151 at a state of a fixed reducedpressure.

[0056] The cooling processing chamber 152 is provided with an openingportion 173, facing the heat processing chamber 151, for performingdelivery of the wafer W from/to the heat processing chamber 151. Theopening portion 173 can be opened and closed by a shutter member 174.The shutter member 174 is raised and lowered for the aforesaid open andclose by means of a raising and lowering cylinder 175.

[0057] Further, in the cooling processing chamber 152, a chill plate 176for cooling the wafer W while the wafer W is mounted thereon isconfigured to be movable in a horizontal direction along a guide plate177 a by means of a moving mechanism 177 b. Thereby, the chill plate 176can get into the heat processing chamber 151 through the opening portion173, receives the wafer W in the heat processing chamber 151 which hasbeen heated by the hot plate 156 from the support pins 158, carries thewafer W into the cooling processing chamber 152, and returns the wafer Wto the support pins 158 after the wafer W is cooled. It should be notedthat the set temperature of the chill plate 176 is, for example, 15° C.to 25° C. and an applicable temperature range of the wafer W to becooled is 200° C. to 470° C.

[0058] Furthermore, an inert gas such as nitrogen gas or the like issupplied into the cooling processing chamber 152 from the top thereofvia a pipe 178. At the lower portion of the cooling processing chamber152 provided is an exhaust port 179 which is connected to a vacuum pump181, for example, via a flexible hose 180. By operation of the vacuumpump 181, the inside of the cooling processing chamber 152 can be set ata pressure lower than atmospheric pressure, for example, about 0.1 torr.Incidentally, the vacuum pump used in the heat processing chamber 151and the vacuum pump used in the cooling processing chamber 152 may becomposed of the same apparatus.

[0059]FIG. 5 is a front view showing the structure of theultraviolet-ray processing station (UV) according to the presentinvention.

[0060] As shown in FIG. 5, in the ultraviolet-ray processing station(UV), a holding plate 51 for holding the wafer W is disposed nearly atthe center thereof. The holding plate is provided with a plurality of,for example, three support pins 52. The delivery of the wafer W to/fromthe tweezers 41, 42, and 43 of the main wafer transfer mechanism 22 isperformed on the support pins 52, and the wafer W is subjected toprocessing by ultraviolet rays while supported by the support pins 52.

[0061] An ultraviolet-ray irradiation lamp 53 for applying ultravioletrays to the front face of the wafer W held by the holding plate 51 isplaced above the holding plate 51. On one side of those, disposed is ablast pipe 55 having a blast port 54 for blasting gas toward a clearancebetween the holding plate 51 and the ultraviolet-ray irradiation lamp53. A switching valve 56 is connected to the blast pipe 55. Theswitching valve 56 performs switching for supplying one of nitrogen gasas an inert gas which is supplied from a nitrogen gas cylinder of whichthe illustration is omitted and oxygen gas which is supplied from anoxygen gas cylinder of which the illustration is omitted to the blastpipe 55 under the control of a control section 57.

[0062] Further, a vertically driving mechanism 58 for vertically drivingthe ultraviolet-ray irradiation lamp 53 is disposed above theultraviolet-ray irradiation lamp 53, and, for example, an illuminancemonitor 59 for monitoring an illuminance of the ultraviolet-rayirradiation lamp 53 is disposed near the holding plate 51. A monitoredresult by the illuminance monitor 59 is sent to the control section 57,and the control section 57 allows the vertically driving mechanism 58 toraise and lower the ultraviolet-ray irradiation lamp 53 so as to keepthe monitored illuminance constant. Thereby, the illuminance of theultraviolet rays applied to the wafer W can be usually kept constant. Itshould be noted that such a control of illuminance can be realized byraising and lowering the holding plate 51 and not the ultraviolet-rayirradiation lamp 53.

[0063] Next, operations in the SOD processing system 1 thus structuredwill be explained. FIG. 6 shows a processing flow in this SOD processingsystem 1.

[0064] First, in the cassette block 10, the unprocessed wafer W istransferred from the wafer cassette CR to the delivery table in thetransfer and chill plate (TCP) included in the third group G3 on theprocessing block 11 side by means of the wafer transfer body 21.

[0065] The wafer W transferred to the delivery table in the transfer andchill plate (TCP) is transferred to the cooling processing station (CPL)by means of the main wafer transfer mechanism 22. In the coolingprocessing station (CPL), the wafer W is cooled to a temperaturesuitable for processing in the SOD coating processing station (SCT)(step 601).

[0066] The wafer W which has undergone the cooling processing in thecooling processing station (CPL) is transferred to the SOD coatingprocessing station (SCT) via the main wafer transfer mechanism 22. Inthe SOD coating processing station (SCT), the wafer W is subjected toSOD coating processing (step 602).

[0067] The wafer W which has undergone the SOD coating processing in theSOD coating processing station (SCT) is transferred to the agingprocessing station (DAC) via the main wafer transfer mechanism 22 andsubjected to aging processing, whereby an insulating film material onthe wafer W is gelled (step 603).

[0068] The wafer W which has undergone the aging processing in the agingprocessing station (DAC) is transferred to the solvent exchangeprocessing station (DSE) via the main wafer transfer mechanism 22. Inthe solvent exchange processing station (DSE), a chemical for exchangeis supplied to the wafer W and processing for exchanging a solvent inthe insulating film applied on top of the wafer for another solvent isperformed (step 604).

[0069] The wafer W which has undergone the exchange processing in thesolvent exchange processing station (DSE) is transferred to thelow-temperature heat processing station (LHP) by means of the main wafertransfer mechanism 22. In the low-temperature heat processing station(LHP), the wafer W undergoes low-temperature heat processing (step 605).

[0070] The wafer W which has undergone the low-temperature heatprocessing in the low-temperature heat processing station (LHP) istransferred to the ultraviolet-ray processing station (UV) by means ofthe main wafer transfer mechanism 22. In the ultraviolet-ray processingstation (UV), the wafer W is subjected to processing by ultraviolet rayswith a wavelength of about 172 nm (step 606). In this processing byultraviolet rays, nitrogen gas is first blasted from the blast port 54of the blast pipe 55, whereby the inside of the ultraviolet-rayprocessing station (UV) is brought to a nitrogen gas atmosphere, and inthat state, ultraviolet rays are applied, for example, for one minutefrom the ultraviolet-ray irradiation lamp 53 (step 606 a). Next, oxygengas is blasted from the blast port 54 of the blast pipe 55, whereby theinside of the ultraviolet-ray processing station (UV) is brought to anoxygen gas atmosphere, for example, for ten seconds (step 606 b). Asdescribed above, in this embodiment, ultraviolet rays are applied to thefront face of the insulating film material applied on the wafer W in thenitrogen atmosphere, and thereafter the atmosphere over the front faceof the insulating film material is brought to an oxygen gas atmosphereto generate oxygen radicals (O*), so that the front face of theinsulating film can be efficiently made smaller in contact angle.Incidentally, the above-described step 606 a and step 606 b may beperformed several times. As for the oxygen gas atmosphere here in thepresent invention, oxygen is suitably contained at least 5% or more inthe gas. Though 100% of oxygen gas is used in this embodiment, air canbe used instead. Further, the ultraviolet-ray irradiation lamp and thewafer W are separated by about 5 mm in this embodiment.

[0071] Thereafter, nitrogen gas is blasted for about 30 seconds from theblast port 54 of the blast pipe 55, whereby the inside of theultraviolet-ray processing station (UV) is exchanged for a nitrogen gasatmosphere.

[0072] The wafer W which has been subjected to the processing byultraviolet rays is transferred to the cooling processing station (CPL)by means of the main wafer transfer mechanism 22. In the coolingprocessing station (CPL), the wafer W is cooled (step 607).

[0073] The wafer W which has undergone the cooling processing in thecooling processing station (CPL) is transferred again to the SOD coatingprocessing station (SCT) via the main wafer transfer mechanism 22. Inthe SOD coating processing station (SCT), the wafer W is subjected to asecond time of SOD coating processing (step 608). At that time, thefront face of the insulating film material which has been alreadyapplied on the wafer W is improved in quality so as to be smaller incontact angle by the aforesaid processing by ultraviolet rays, and thuseven if an insulating film material is further applied thereon,projections and depressions do not occur on a front face thereof.

[0074] The wafer W which has undergone the SOD coating processing in theSOD coating processing station (SCT) is transferred to the agingprocessing station (DAC) via the main wafer transfer mechanism 22 andsubjected to aging processing, whereby the insulating film material onthe wafer W is gelled (step 609).

[0075] The wafer W which has undergone the aging processing in the agingprocessing station (DAC) is transferred to the solvent exchangeprocessing station (DSE) via the main wafer transfer mechanism 22. Inthe solvent exchange processing station (DSE), a chemical for exchangeis supplied to the wafer W and processing for exchanging a solvent inthe insulating film applied on top of the wafer for another solvent isperformed (step 610).

[0076] The wafer W which has undergone the exchange processing in thesolvent exchange processing station (DSE) is transferred to thelow-temperature heat processing station (LHP) by means of the main wafertransfer mechanism 22. In the low-temperature heat processing station(LHP), the wafer W undergoes low-temperature heat processing (step 611).

[0077] The wafer W which has undergone the low-temperature heatprocessing in the low-temperature heat processing station (LHP) istransferred to the low-oxygen and high-temperature heat processingstation (OHP) by means of the main wafer transfer mechanism 22. In thelow-oxygen and high-temperature heat processing station (OHP), the waferW undergoes high-temperature heat processing in a low-oxygen atmosphere(step 612).

[0078] The wafer W which has undergone the high-temperature heatprocessing in the low-oxygen and high-temperature heat processingstation (OHP) is transferred to the low-oxygen curing and coolingprocessing station (DCC) by means of the main wafer transfer mechanism22. In the low-oxygen curing and cooling processing station (DCC), thewafer W undergoes high-temperature heat processing in a low-oxygenatmosphere and then cooling processing (step 613).

[0079] Here, the processing in the step 613 will be explained in moredetail using FIG. 11 and FIG. 12.

[0080] The wafer W is delivered from the main wafer transfer mechanism22 onto the support pins 58 in a state in which the top portion of theprocessing chamber main body 153 is opened and the support pins 158protrude from the front face of the hot plate 156. At that time,nitrogen gas is blasted into the heat processing chamber 151 from thegas blast ports 162 of the ring pipe 163, whereby the inside of the heatprocessing chamber 151 is set at a pressure higher than a pressure onthe main wafer transfer mechanism 22 side. Thereby, it is avoided forparticles to be drawn from the main wafer transfer mechanism 22 sideinto the heat processing chamber 151.

[0081] Subsequently, the lid body 154 is lowered and the top openingportion of the processing chamber main body 153 is closed with the lidbody 154, thereby forming a sealed space in the heat processing chamber151. Then, a blast of nitrogen gas into the heat processing chamber 151from the gas blast ports 162 of the ring pipe 163 is stopped and thevacuum pump 170 is operated to set the inside of the heat processingchamber 151 at a pressure lower than atmospheric pressure, for example,about 0.1 torr. Thereafter, the support pins 158 are lowered and retractfrom the front face of the hot plate 156, whereby the wafer W is mountedon the hot plate 156 and heat processing for the wafer W is started.Since the wafer W is subjected to the heat processing at a pressurelower than atmospheric pressure in the heat processing chamber 151 asdescribed above, it is possible to quickly perform the heat processingperformed for the wafer W and to form a layer insulating film which ishigh in dielectric constant and is a uniform porous film on the wafer W.

[0082] Next, the blast of nitrogen gas is started into the heatprocessing chamber 151 from the gas blast ports 162 of the ring pipe 163to purge the inside of the heat processing chamber 151 by the nitrogengas, the support pins 158 are raised to protrude from the front face ofthe hot plate 156, and the lid body 154 is raised, whereby the topportion of the processing chamber main body 153 is opened. The blast ofthe nitrogen gas into the heat processing chamber 151 from the gas blastports 162 of the ring pipe 163 is continued during that time. Thereby,particles are never drawn from the main wafer transfer mechanism 22 sideinto the heat processing chamber 151.

[0083] Next, the chill plate 176 in the cooling processing chamber 152gets into the heat processing chamber 151 through the opening portion173, receives the wafer W from the support pins 158, and carries thewafer W into the cooling processing chamber 152. During that time,nitrogen gas is supplied into the cooling processing chamber 152 throughthe pipe 178. Thereby, oxidation of the wafer W is prevented. Forexample, nitrogen gas is supplied to the cooling processing chamber 152too much to thereby bring the inside of the cooling processing chamber152 more positive in pressure than the inside of the heat processingchamber 151, whereby it is avoided for particles to be drawn into thecooling processing chamber 152. Contrary to that, nitrogen gas issupplied to the cooling processing chamber 152 too little to therebybring the inside of the cooling processing chamber 152 more negative inpressure than the inside of the heat processing chamber 151, whereby itis avoided for particles to be drawn into the heat processing chamber151. In other words, the essence is to control drawing of particles bygiving a relation of negative pressure or positive pressure between theheat processing chamber 151 and the cooling processing chamber 152.

[0084] Next, the opening portion 173 is closed by the shutter member174, and the supply of nitrogen gas into the cooling processing chamber152 is stopped. Further, the inside of the cooling processing chamber152 is set to a pressure lower than atmospheric pressure by theoperation of the vacuum pump 181, and the cooling processing for thewafer W is performed. The cooling processing is performed under thereduced pressure as described above, whereby the cooling processing canbe quickly and uniformly performed for the wafer W.

[0085] Next, the operation of the vacuum pump 181 is stopped, the supplyof nitrogen gas into the cooling processing chamber 152 is started, andthe opening portion 173 is opened. The chill plate 176 gets into theheat processing chamber 151 through the opening portion 173 and deliversthe wafer W to the support pins 158. At that time, the blast of nitrogengas into the heat processing chamber 151 from the gas blast ports 162 ofthe ring pipe 163 is continued. Thereby, particles are never drawn fromthe main wafer transfer mechanism 22 side into the heat processingchamber 151.

[0086] The wafer W which has been subjected to the processing in thelow-oxygen curing and cooling processing station (DCC) is transferred tothe chill plate in the transfer and chill plate (TCP) by means of themain wafer transfer mechanism 22. The wafer W undergoes coolingprocessing on the chill plate in the transfer and chill plate (TCP)(step 614). In this embodiment, an insulating film with a thickness ofabout 500 nm can be obtained by one time of SOD coating processing andthus an insulating film with a thickness of 1 μm can be obtained by atotal of two times of SOD coating processing.

[0087] The wafer W which has undergone the cooling processing on thechill plate in the transfer and chill plate (TCP) is transferred to thewafer cassette CR via the wafer transfer body 21 in the cassette block10.

[0088] By the above-described SOD processing, a flat layer insulatingfilm without projections and depressions can be formed on the front faceof the wafer W.

[0089] Next, a second embodiment of an ultraviolet-ray processingstation according to the present invention will be explained.

[0090]FIG. 7 is a front view showing the structure of theultraviolet-ray processing station (UV) according to the secondembodiment.

[0091] In the ultraviolet-ray processing station (UV) shown in FIG. 7, aholding plate 71 for holding the wafer W is disposed nearly at thecenter thereof. The holding plate 71 is provided with a plurality, forexample, three support pins 72. The support pins 72 are configured to beraised and lowered above the holding plate 71 by means of a verticallydriving mechanism 73 which is provided on the rear face side of theholding plate 71. Further, an ultraviolet-ray irradiation lamp 74 isdisposed above the front face of the wafer W held by the holding plate71. Here, an area close to the ultraviolet-ray irradiation lamp 74 isregarded as a first area {circle over (1)}, and an area close to theholding plate 71 thereunder is regarded as a second area {circle over(2)}. On one side of these areas, a nitrogen gas blast pipe 75 forblasting nitrogen gas as an inert gas supplied from a nitrogen gascylinder of which the illustration is omitted toward the first area{circle over (1)} is disposed, and an oxygen gas blast pipe 76 forblasting oxygen gas supplied from an oxygen gas cylinder of which theillustration is omitted toward the second area {circle over (2)} isdisposed under the first area {circle over (1)}. Nitrogen gas of lowmolecular weight is blasted to the first area {circle over (1)} andoxygen gas of high molecular weight is blasted to the second area{circle over (2)} under the first area {circle over (1)} as describedabove, thereby reducing mixture of nitrogen gas in the first area{circle over (1)} and oxygen gas in the second area {circle over (2)}.

[0092] In a state in which the tips of the support pins 72 are withinthe first area {circle over (1)}, the wafer W is delivered from thetweezers 41, 42, and 43 of the main wafer transfer mechanism 22 to thesupport pins 72. Then, ultraviolet rays are applied to the front face ofthe wafer W from the ultraviolet-ray irradiation lamp 74 in the firstarea {circle over (1)}. Thereafter, the support pins 72 are lowered,whereby the wafer W is moved to the second area {circle over (2)}, andoxygen radicals (O*) are generated in the second area {circle over (2)}.Incidentally, the above-described raising and lowering operation may berepeated twice or more.

[0093] As described above, in this embodiment, a nitrogen gas atmospherecan be switched to an oxygen gas atmosphere only by lowering the wafer Wfrom the first area {circle over (1)} to the second area {circle over(2)}, and an oxygen gas atmosphere can be switched to a nitrogen gasatmosphere only by raising the wafer W from the second area {circle over(2)} to the first area {circle over (1)}. Consequently, the front faceof the insulating film applied on the wafer W can be efficiently madesmaller in contact angle.

[0094] It should be noted that in the second embodiment, the supportpins 72 are raised and lowered to thereby move the wafer W between thefirst area {circle over (1)} and the second area {circle over (2)}.However, it is also suitable to configure that support pins 82 providedat a holding plate 81 are fixed and the holding plate 81 itself israised and lowered by a vertically driving mechanism 83 as shown in FIG.8 as a third embodiment. In FIG. 8, the same numerals and symbols aregiven to the same components as those shown in FIG. 7.

[0095] Next, a fourth embodiment of an ultraviolet-ray processingstation according to the present invention will be explained.

[0096]FIG. 9 is a front view showing the structure of theultraviolet-ray processing station (UV) according to the fourthembodiment, and FIG. 10 is a plan view thereof.

[0097] In the ultraviolet-ray processing station (UV) shown in thesedrawings, a holding plate 91 for holding the wafer W is disposed nearlyat the center thereof. The holding plate 91 is provided with a pluralityof, for example, three support pins 92. The holding plate 91 is rotatedby means of a rotationally driving mechanism 93 which is disposed on therear face side thereof.

[0098] Further, an oblong ultraviolet-ray irradiation lamp 94 isdisposed above the holding plate 91 along a direction of a diameter ofrotation of the holding plate 91.

[0099] An oblong nitrogen gas blast nozzle 95 as an inert gas blastportion for blasting nitrogen gas toward the front face of the wafer Wheld on the holding plate 91 is disposed along one radial direction froman area close to the center on one side of the ultraviolet-rayirradiation lamp 94, and an oblong oxygen gas blast nozzle 96 as anoxygen gas blast portion for blasting oxygen gas toward the front faceof the wafer W held on the holding plate 91 is disposed along theaforesaid one radial direction from an area close to the center on theother side of the ultraviolet-ray irradiation lamp 94. Similarly, anoblong oxygen gas blast nozzle 97 for blasting oxygen gas toward thefront face of the wafer W held on the holding plate 91 is disposed alongthe other radial direction from an area close to the center on the oneside of the ultraviolet-ray irradiation lamp 94, and an oblong nitrogengas blast nozzle 98 for blasting nitrogen gas toward the front face ofthe wafer W held on the holding plate 91 is disposed along the aforesaidother radial direction from an area close to the center on the otherside of the ultraviolet-ray irradiation lamp 94.

[0100] When the holding plate 91 is rotated in a direction of arrows inFIG. 10, nitrogen gas is first blasted to the front face of the wafer W,whereby the front face of the wafer W is in a nitrogen gas atmosphereand then irradiated with ultraviolet rays. Thereafter, oxygen gas isblasted to the front face of the wafer W, whereby the front face of thewafer W is brought into an oxygen gas atmosphere, and oxygen radicalsare generated. The holding plate 91 is continuously rotated, whereby theaforesaid operations are repeated. Consequently, according to thisembodiment, the front face of the insulating film on the wafer can beefficiently made smaller in contact angle.

[0101] Next, a fifth embodiment of an ultraviolet-ray processing stationaccording to the present invention will be explained.

[0102]FIG. 13 is a front view showing the structure of theultraviolet-ray processing station (UV) according to the fifthembodiment.

[0103] In the ultraviolet-ray processing station (UV) according to thefifth embodiment, a hot plate 251 is used as the holding plate 51 of theultraviolet-ray processing station (UV) according to the firstembodiment. The hot plate 251 can be heated to a temperature of about120° C., and the wafer W is mounted on the hot plate 251 which is set ata temperature of 120° C. while ultraviolet rays are applied to the waferW in the fifth embodiment. The wafer W is irradiated with ultravioletrays while heated as described above, whereby generation of oxygenradicals (O*) is accelerated more, with the result that a period of timeof ultraviolet-ray irradiation can be reduced as compared with the firstembodiment.

[0104] Next, a sixth embodiment according to the present invention willbe explained.

[0105] In the first embodiment, the inside of the ultraviolet-rayprocessing station (UV) is brought to an oxygen gas atmosphere after anitrogen gas atmosphere during ultraviolet-ray irradiation. In the sixthembodiment, the inside of the ultraviolet-ray processing station (UV) isbrought to a mixed gas atmosphere made by mixture of 95% of nitrogen gasand 5% of oxygen gas during the ultraviolet-ray irradiation. The mixtureratio of an inert gas and oxygen gas is limited as described above,thereby keeping a propagation efficiency of ultraviolet rays good andefficiently making the front face of the insulating film smaller incontact angle without inhibiting generation of oxygen radicals (O*).Accordingly, the operation of switching the atmosphere in theultraviolet-ray processing station (UV) during ultraviolet-rayirradiation as in the first embodiment becomes unnecessary, resulting inimproved operating efficiency. Further, a period of processing time inthe ultraviolet-ray processing station (UV) is 1 minute 40 seconds inthe first embodiment, but it can be reduced to 1 minute 10 seconds inthe sixth embodiment.

[0106] Next, a seventh embodiment according to the present inventionwill be explained.

[0107] In the first embodiment, the inside of the ultraviolet-rayprocessing station (UV) is set to be switched to an oxygen gasatmosphere after a nitrogen gas atmosphere during ultraviolet-rayirradiation. In the seventh embodiment, the atmosphere in theultraviolet-ray processing station (UV) is set such that oxygen gastherein is gradually increased. For example, the setting is made suchthat nitrogen gas is supplied into the ultraviolet-ray processingstation (UV) at the time of start of ultraviolet-ray irradiation, amixed gas of nitrogen gas and oxygen gas is supplied into theultraviolet-ray processing station (UV) with oxygen gas being graduallyincreased with time, and the mixture ratio of the mixed gas becomes aratio of 95% of nitrogen gas to 5% of oxygen gas at the time ofcompletion of the ultraviolet-ray irradiation. Ultraviolet rays areapplied with oxygen gas being gradually increased as above, whereby whenthe inside of the ultraviolet-ray processing station (UV) is exchangedfor a nitrogen gas atmosphere after the ultraviolet-ray irradiation, aperiod of time for purging nitrogen gas can be shortened.

[0108] Next, an eighth embodiment according to the present inventionwill be explained.

[0109] The ultraviolet-ray processing station (UV) is provided toperform ultraviolet-ray processing in the first embodiment. However, itis possible to provide ultraviolet-ray irradiation means in the coolingprocessing chamber in the low-oxygen curing and cooling processingstation (DCC) and to perform the ultraviolet-ray processing which isperformed in the step 606 in the cooling processing chamber in thelow-oxygen curing and cooling processing station (DCC).

[0110]FIG. 14 is a sectional view of a low-oxygen curing and coolingprocessing station (DCC) according to the eighth embodiment. In FIG. 14,an ultraviolet-ray irradiation lamp 53 is disposed above a chill plate176 in a cooling processing chamber 152 of the low-oxygen curing andcooling processing station (DCC). Further, a blast pipe 255 including ablast port 254 for blasting gas toward a clearance between the chillplate 176 and the ultraviolet-ray irradiation lamp 53 is disposed. Aswitching valve 256 is connected to the blast pipe 255. The switchingvalve 256 performs switching for supplying one of nitrogen gas as aninert gas and oxygen gas which is supplied from an oxygen gas cylinderto the blast pipe 255 under the control of the control section.

[0111] The ultraviolet-ray irradiation means is provided in the coolingprocessing chamber of the low-oxygen curing and cooling processingstation (DCC), whereby processing in the step 606 and the step 613 canbe performed in the same station.

[0112] Nitrogen gas is used as an inert gas in the aforesaidembodiments, but argon gas or the like can also be used. Attenuation ofultraviolet rays which propagate in gas is smaller and energy efficiencyis better in the case where argon gas is used than in the case wherenitrogen gas is used.

[0113] The aforesaid embodiments have the intention of clarifyingtechnical meaning of the present invention. Therefore, the presentinvention is not intended to be limited to the above concreteembodiments and to be interpreted in a narrow sense, and various changesmay be made therein without departing from the spirit of the presentinvention and within the meaning of the claims.

What is claimed is:
 1. A substrate processing method, comprising thesteps of: applying an insulating film material on a substrate;performing processing by ultraviolet rays for a front face of theapplied insulating film material; and further applying an insulatingfilm material on the applied insulating film material after theultraviolet-ray processing step.
 2. The method as set forth in claim 1,wherein said ultraviolet-ray processing step comprises the steps of:applying ultraviolet rays to the front face of the applied insulatingfilm material in an inert gas atmosphere; and thereafter bringing anatmosphere over the front face of the insulating film material to anoxygen atmosphere.
 3. The method as set forth in claim 2, wherein theoxygen atmosphere is an atmosphere with an oxygen content of 5% or more.4. The method as set forth in claim 1, wherein heat processing isperformed for the substrate after said insulating film material coatingstep and before said ultraviolet-ray processing step, and whereincooling processing is performed for the substrate after saidultraviolet-ray processing step and before said further insulating filmmaterial coating step.
 5. The method as set forth in claim 1, whereinsaid ultraviolet-ray processing step is performed under a mixed gasatmosphere in which an inert gas and oxygen are mixed.
 6. The method asset forth in claim 5, wherein the oxygen is contained 5% in the mixedgas.
 7. The method as set forth in claim 1, wherein said ultraviolet-rayprocessing step is performed under an atmosphere of which oxygen contentis gradually increased.
 8. The method as set forth in claim 1, whereinheat processing is being performed for the substrate during saidultraviolet-ray processing step.
 9. A substrate processing method,comprising the steps of: applying an insulating film material on asubstrate; applying ultraviolet rays to a front face of the insulatingfilm material in an inert gas atmosphere; and thereafter bringing anatmosphere over the insulating film material to an oxygen atmosphere.10. A substrate processing method, comprising the steps of: applying aninsulating film material on a substrate; applying ultraviolet rays to afront face of the insulating film material in a processing chamber withan inert gas atmosphere; thereafter applying ultraviolet rays to thefront face of the insulating film material under an atmosphere in theprocessing chamber into which oxygen has been allowed to flow; andbringing the inside of the processing chamber to an inert gasatmosphere.
 11. A substrate processing apparatus, comprising: a holdingplate for holding a substrate; an ultraviolet-ray irradiation lampdisposed above the holding plate for applying ultraviolet rays to afront face of the substrate; means for bringing a portion between thesubstrate held on the holding plate and the ultraviolet-ray irradiationlamp to an inert gas atmosphere; and means for switching at least theinert gas atmosphere over the front face of the substrate held on theholding plate to an oxygen atmosphere.
 12. The method as set forth inclaim 11, wherein the oxygen atmosphere contains 5% or more of oxygen.13. A substrate processing apparatus, comprising: a holding plate forholding a substrate and ascendable and descendable between a first areaand a second area below the first area; a vertically driving mechanismfor vertically driving the holding plate between the first area and thesecond area; an ultraviolet-ray irradiation lamp disposed above theholding plate for applying ultraviolet rays to a front face of thesubstrate held by the holding plate; means for blasting an inert gastoward the first area; and means for blasting oxygen gas toward thesecond area.
 14. A substrate processing apparatus, comprising: a holdingplate for holding a substrate to be ascendable and descendable between afirst area and a second area below the first area; a vertically drivingmechanism for vertically driving the substrate held by the holding platebetween the first area and the second area; an ultraviolet-rayirradiation lamp disposed above the holding plate for applyingultraviolet rays to a front face of the substrate held by the holdingplate; means for blasting an inert gas toward the first area; and meansfor blasting oxygen gas toward the second area.
 15. A substrateprocessing apparatus, comprising: a holding plate for holding asubstrate and rotatable; a rotationally driving mechanism forrotationally driving the holding plate; an ultraviolet-ray irradiationlamp, disposed above the holding plate along at least a radial directionof rotation of the holding plate, for applying ultraviolet rays to thesubstrate held by the holding plate; an inert gas blast portion,disposed along one side of the ultraviolet-ray irradiation lamp, forblasting an inert gas toward the front face of the substrate held on theholding plate; and an oxygen gas blast portion, disposed along the otherside of the ultraviolet-ray irradiation lamp, for blasting oxygen gastoward the front face of the substrate held on the holding plate.